Production of isomaltulose using Erwinia sp. D12 cells: Culture medium optimization and cell immobilization in alginate

Isomaltulose is a structural isomer of sucrose commercially used in food industries. Glucosyltransferase produced by Erwinia sp. D12 catalyses an intramolecular transglucosylation of sucrose giving isomaltulose. An experimental Design and Response Surface Methodology were applied for the optimization of the nutrient concentration in the culture medium for enzyme production in shaken flasks at 200 rpm and 30 °C. A higher production of glucosyltransferase (7.47 Uml⁻¹) was observed in the culture medium containing sugar cane molasses (160 gl⁻¹), bacteriological peptone (20 gl⁻¹) and yeast extract Prodex Lac SD^® (15 gl⁻¹) after 8 h, at 30 °C. The highest production of glucosyltransferase in the 6.6-l bioreactor (14.6 Uml⁻¹) was obtained in the optimized culture medium after 10 h at 26 °C. When Erwinia sp. D12 cells were immobilized in sodium alginate, it was verified that sodium alginate solution A could be substituted by a cheaper one, sodium alginate solution B. Using a 40% cell suspension and 2% sodium alginate solution B for cell immobilization in a packed-bed reactor, 64.1% conversion of sucrose to isomaltulose was obtained. The packed-bed reactor with immobilized cells plus glutaraldehyde and polyethylenimine solutions remained in a pseudo-steady-state for 180 h.     

Optimization of fermentation parameters in phage production using response surface methodology

Previously, we used computer-controlled fermentation technology to improve the yield of filamentous phage produced in Escherichia coli by 10-fold (Grieco et?al., Bioprocess Biosyst Eng 32:773-779, 2009). In the current study, three major fermentation parameters (temperature, dissolved oxygen [DO], and pH) were investigated using design of experiments (DOE) methodology. Response surface methodology (RSM) was employed to create a process model and determine the optimal conditions for maximal phage production. The experimental data fitted best to a quadratic model (p?相似文献   

Optimization of L-asparaginase production from novel Enterobacter sp., by submerged fermentation using response surface methodology

The culture conditions and nutritional rations influencing the production of extra cellular antileukemic enzyme by novel Enterobacter aerogenes KCTC2190/MTCC111 were optimized in shake-flask culture. Process variables like pH, temperature, incubation time, carbon and nitrogen sources, inducer concentration, and inoculum size were taken into account. In the present study, finest enzyme activity achieved by traditional one variable at a time method was 7.6 IU/mL which was a 2.6-fold increase compared to the initial value. Further, the L-asparaginase production was optimized using response surface methodology, and validated experimental result at optimized process variables gave 18.35 IU/mL of L-asparaginase activity, which is 2.4-times higher than the traditional optimization approach. The study explored the E. aerogenes MTCC111 as a potent and potential bacterial source for high yield of antileukemic drug.     

Optimization of fermentation parameters for the biomass and DHA production of Schizochytrium limacinum OUC88 using response surface methodology

Fermentation parameters for biomass and DHA production of Schizochytrium limacinum OUC88 in a fermenter (working volume 7 L) were optimized using Plackett–Burman and central composite rotatable design. Out of 10 factors studied by Plackett–Burman design, 4 influenced the biomass production significantly. Central composite rotatable design was used to optimize the significant factors and response surface plots were generated. Using these response surface plots and point prediction, optimized values of the factors were determined as follows temperature (°C) 23 °C, aeration rate 1.48 L min⁻¹ L⁻¹, agitation 250 rpm and inoculum cells in mid-exponential phase, the maximum yield of DCW and DHA were 24.1 and 4.7 g L⁻¹, respectively. These predicted values were also verified by validation experiments.     

Palatinose production by free and Ca-alginate gel immobilized cells of Erwinia sp.

Palatinose is a non-cariogenic disaccharide obtained from the enzymatic conversion of sucrose, used in food industries as a sugar substitute. Free and Ca-alginate immobilized cells of Erwinia sp. D12 were used to produce palatinose from sucrose. Palatinose production was studied in a repeated-batch process using different immobilized biocatalysts: whole cells, disrupted cells and glucosyltransferase. Successive batches were treated with the immobilized biocatalyst, but a decrease in palatinose production was observed. A continuous process using a packed-bed reactor was investigated, and found to produce 55–66% of palatinose during 17 days using immobilized cells treated with glutaraldehyde and a substrate flow speed of 0.56 ml min⁻¹. However, immobilized cells in a packed-bed reactor failed to maintain the palatinose production for a prolonged period. The free cells showed a high conversion rate using batch fermentation, obtaining a palatinose yield of 77%. The cells remained viable for 16 cycles with high palatinose yields (65–77%). Free Erwinia sp. D12 cells supported high production levels in repeated-batch operations, and the results showed the potential for repeated reuse.     

Optimization of fermentation conditions for the production of ethanol from sago starch using response surface methodology

The quantitative effects of temperature, pH and time of fermentation were investigated on simultaneous saccharification and fermentation (SSF) of ethanol from sago starch with glucoamylase (AMG) and Zymomonas mobilis ZM4 using a Box–Wilson central composite design protocol. The SSF process was studied using free enzyme and free cells and it was found that with sago starch, maximum ethanol concentration of 70.68 g/l was obtained using a starch concentration of 140 g/l, which represents an ethanol yield of 97.08%. The optimum conditions for the above yield were found to be a temperature of 36.74 °C, pH of 5.02 and time of fermentation of 17 h. Thus by using the central composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

Solid-state fermentation for xylanase production by Thermoascus aurantiacus using response surface methodology

We investigated xylanase production by Thermoascus aurantiacus using semisolid fermentation. Multivariant statistical approaches were employed to evaluate the effects of several variables (initial moisture in the medium, cultivation time, inoculum level, and bagasse mass) on xylanase production. The initial moisture content and bagasse mass were the most important factors affecting xylanase activity. The xylanase activity produced by the fungus under the optimized conditions (81% moisture content and 17 g bagasse) was found to be 2700 U per gram of initial dry matter, whereas its value predicted by a polynomial model was 2400 U per gram of initial dry matter. Received: 4 December 1998 / Received revision: 15 March 1999 / Accepted: 16 May 1999     

Optimization of mycophenolic acid production in solid state fermentation using response surface methodology

Mycophenolic acid (MPA) can be produced in solid state fermentation. An isolate of Penicillium brevi-compactum ATCC 16024 grown on moist wheat bran produced a titre of 425 mg per kg of wheat bran. Central composite rotatable design and response surface methodology were employed to derive a statistical model for media optimization towards production of mycophenolic acid. Five levels with a five factorial design were adopted. The correlation coefficient was 0.82, ensuring a satisfactory adjustment of the model to the experimental values. This statistical design was very effective in improving the titre of mycophenolic acid up to 3286 mg per kg of wheat bran. Received 24 July 1998/ Accepted in revised form 4 December 1998     

Optimization of microbiological parameters for enhanced griseofulvin production using response surface methodology

Central composite design was used to determine the optimal levels of microbiological parameters, viz., slant age, seed age and inoculum level, for enhanced griseofulvin production by Penicillium griseofulvum MTCC 1898 and Penicillium griseofulvum MTCC 2004 in shake flask fermentation. The optimal levels of slant age, seed age and inoculum level for Penicillium griseofulvum MTCC 1898 were found to be 8.8772 days, 4.2093 days, 12% (v/v) (᷁.56 kg dry cell mass/m³) and for Penicillium griseofulvum MTCC 2004, 8.221 days, 3.4875 days and 9% (v/v) (̀.09 kg dry cell mass/m³) respectively. The yield of griseofulvin under optimal conditions was found to be 1.65 times for Penicillium griseofulvum MTCC 1898 and 1.07 times for Penicillium griseofulvum MTCC 2004 higher than that obtained using unoptimized conditions. The fermentation time for maximum production of griseofulvin by Penicillium griseofulvum MTCC 1898 and Penicillium griseofulvum MTCC 2004 decreased by 4 days and 2 days respectively.     

Optimization of methane fermentation from effluent of bio-hydrogen fermentation process using response surface methodology

The individual effects and interactive effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration on the methane yield from the effluent of bio-hydrogen fermentation of food waste were investigated in this study. A central composite design (CCD) and response methodology (RSM) were employed in designing the experiments, in order to determine the optimum conditions for methane fermentation. The experiment results showed that the effects of substrate concentration, ratio of inoculum to substrate, Ca(2+) concentration were statistically significant at 5% level. The interactive effect of substrate concentration and ratio of inoculum to substrate was significant, however the interactive effect of substrate concentration and Ca(2+) concentration, ratio of inoculum to substrate and Ca(2+) concentration were found to be insignificant at 5% level. A maximum yield of 565.76 ml CH(4)/g VS(added) was estimated under the optimum conditions for substrate concentration 7.77 g of VS/l, inoculum to substrate ratio of 2.81 and calcium concentration of 380.82 mg/l. Verification experiment of the estimated optimum conditions confirmed that the RSM was useful for optimizing the methane yield from effluent of bio-hydrogen fermentation of food waste.     

Medium optimization for antifungal active substances production from a newly isolated Paenibacillus sp. using response surface methodology

Statistics based experimental designs were used to optimize the medium for antifungal active substances production from a newly isolated Paenibacillus polymyxa Cp-S316 in shaker flask cultivation. The medium components having significant effect on the production were first identified using a fractional factorial design. Then steepest ascent method was employed to approach the experimental design space, followed by an application of response surface methodology for further optimization. A quadratic model was found to fit the antifungal active substances production. Response surface analysis revealed that the optimum values of the tested variables for the production of active substances were 12.3 (g/l) lactose, 17.5 (g/l) peptone, 0.4 (g/l) sodium nitrate, 4.5 (g/l) magnesium sulfate and 100 (g/l) potato. A production of 4687.71mug/ml, which was in agreement with the prediction, was observed in verification experiment. In comparison to the production of basal medium, 3.05-fold increase had been obtained.     

Optimization of medium constituents and fermentation conditions for the production of ethanol from palmyra jaggery using response surface methodology

The quantitative effects of sugar concentration, nitrogen concentration, EDTA, temperature, pH and time of fermentation on ethanol production were optimized using a Box-Wilson central composite design (CCD) experiment. It was found that palmyra jaggery (sugar syrup from the palmyra palm) is a suitable substrate for the production of high concentrations of ethanol using Saccharomyces cerevisiae NCIM 3090 by submerged fermentation. A maximum ethanol concentration of 129.4 g/l was obtained after optimizing media components and conditions of fermentation. The optimum values were a temperature of 26.2 °C, pH of 8.4, time of fermentation of 4.2 days with 398.5 g of substrate/l, 3.1 g of urea/l and 0.51 g of EDTA/l. Thus by using the CCD, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

响应面法优化荷叶离褶伞菌丝体产漆酶条件

为了对荷叶离褶伞产漆酶条件进行优化,在单因素实验基础上,通过最陡爬坡实验(PB)对培养基8因素进行筛选,获得影响产漆酶的3个显著性因素:葡萄糖,pH和KH₂PO₄;通过中心组合(CCD)设计及响应面分析确定了最优发酵条件:葡萄糖20.09g/L,酪蛋白1.5g/L,酵母提取物1.5g/L,MgSO₄ 3g/L,CuSO₄ 3.75mg/L,KH₂PO₄ 3.97g/L,pH 4.98,VB₁ 0.1g/L,愈创木酚12mg/L,该条件下,漆酶酶活为829.83U/mL,较未优化对照提高46.6%.     

Optimization of antifungal lipopeptide production from Bacillus sp. BH072 by response surface methodology

Antifungal lipopeptide produced by Bacillus sp. BH072 was extracted from fermentation liquor and determined as iturin A by liquid chromatography-mass spectrometry (LC-MS). For industrial-scale production, the yield of iturin A was improved by optimizing medium components and fermentation conditions. A one-factor test was conducted; fermentation conditions were then optimized by response surface methodology (RSM) to obtain the following: temperature, 29.5°C; pH 6.45; inoculation quantity, 6.7%; loading volume, 100 ml (in 500 ml flasks); and rotary speed, 150 rpm. Under these conditions, the mass concentration of iturin A was increased from 45.30 mg/ml to 47.87 mg/ml. The following components of the medium were determined: carbon sources (glucose, fructose, sucrose, xylose, rhamnose, and soluble starch); nitrogen sources (peptone, soybean meal, NH₄Cl, urea, and ammonium citrate); and metal ions (Zn²⁺, Fe³⁺, Mg²⁺, Mn²⁺, Ca²⁺, and K⁺). The effects of these components on iturin A production were observed in LB medium. We selected sucrose, soybean meal, and Mg²⁺ for RSM to optimize the conditions because of several advantages, including maximum iturin A production, high antifungal activity, and low cost. The optimum concentrations of these components were 0.98% sucrose, 0.94% soybean meal, and 0.93% Mg²⁺. After iturin A production was optimized by RSM, the mass concentration reached 52.21 mg/ml. The antifungal specific activity was enhanced from 350.11 AU/mg to 513.92 AU/mg, which was 46.8% higher than the previous result. The present study provides an important experimental basis for the industrial-scale production of iturin A and the agricultural applications of Bacillus sp. BH072.     

Optimization of l‐DOPA production by Brevundimonas sp. SGJ using response surface methodology

l ‐DOPA (3,4‐dihydroxyphenyl‐l ‐alanine) is an extensively used drug for the treatment of Parkinson's disease. In the present study, optimization of nutritional parameters influencing l ‐DOPA production was attempted using the response surface methodology (RSM) from Brevundimonas sp. SGJ. A Plackett–Burman design was used for screening of critical components, while further optimization was carried out using the Box–Behnken design. The optimized levels of factors predicted by the model were pH 5.02, 1.549 g l^?1 tryptone, 4.207 g l^?1 l ‐tyrosine and 0.0369 g l^?1 CuSO₄, which resulted in highest l ‐DOPA yield of 3.359 g l^?1. The optimization of medium using RSM resulted in a 8.355‐fold increase in the yield of l ‐DOPA. The anova showed a significant R² value (0.9667), model F‐value (29.068) and probability (0.001), with insignificant lack of fit. The highest tyrosinase activity observed was 2471 U mg^?1 at the 18th hour of the incubation period with dry cell weight of 0.711 g l^?1. l ‐DOPA production was confirmed by HPTLC, HPLC and GC‐MS analysis. Thus, Brevundimonas sp. SGJ has the potential to be a new source for the production of l ‐DOPA.     

Influence of media composition on xylitol fermentation by Candida guiliiermondii using response surface methodology

Summary The bioconversion of xylose to xylitol by the yeast Candida guilliermondii FTI 20037 was evaluated under different nutritional conditions using rice straw hemicellulose hydrolysate. Statistical designs were used to determine the fermentation medium composition. Ammonium sulfate and rice bran have been identified as required nutrients in the hydrolysate since there was a significant interaction between them. In the presence of both nutrients, the xylitol yield factor (Yp/s) and volumetric productivities (Qp) were 0.68 g/g and 0.54 g/L.h, respectively.     

Optimization of fermentation conditions for the production of ethanol from sago starch by co-immobilized amyloglucosidase and cells of Zymomonas mobilis using response surface methodology

Statistical experimental design was used to optimize the conditions of simultaneous saccharification and fermentation (SSF), viz. temperature, pH and time of fermentation of ethanol from sago starch with co-immobilized amyloglucosidase (AMG) and Zymomonas mobilis MTCC 92 by submerged fermentation. Maximum ethanol concentration of 55.3 g/l was obtained using a starch concentration of 150 g/l. The optimum conditions were found to be a temperature of 32.4 °C, pH of 4.93 and time of fermentation of 17.24 h. Thus, by using SSF process with co-immobilized AMG and Z. mobilis cells MTCC 92, the central composite design (CCD) was found to be the most favourable strategy investigated with respect to ethanol production and enzyme recovery.     

响应面法优化玉米秸秆同步酶解发酵产乙醇条件

对汽爆玉米秸秆同步酶解发酵生产乙醇的条件进行优化。首先利用Fractional Factorial设计法对影响乙醇产量的7个因素进行评价,筛选出具有显著效应的3个因素,即反应温度、酶添加量、总反应时间,再以Box—Behnken设计法及响应面分析法确定主要因素的最佳水平,即反应温度37℃,每g纤维素添加纤维素酶32u,反应时间87h,此时乙醇体积分数达到3．69％。新工艺条件实验结果表明,乙醇体积分数在87h可达到3．76％,和原工艺相比,反应时间缩短了9h,乙醇体积分数提高了13％。     

Optimization of fermentation medium for amidase production by response surface methodology

采用响应面分析方法,对阿萨希丝孢酵母(Trichosporon asahii)ZZB-1产酰胺酶的发酵培养基进行了优化.运用单因子试验筛选出麦芽糖和酵母浸膏为最适碳源、氮源,金属离子Ca2+、Mn2+可提高发酵酰胺酶产量;通过最陡爬坡实验逼近以上4个因子的最大响应区域后,采用Box-Behnken响应面分析法,确定产酰胺酶最佳发酵培养基为麦芽糖18.84 g/L、酵母浸膏9.55 g/L、NaCl 5g/L、KH2 PO41g/L、MgSO4·7H2O 0.2 g/L、FeSO40.001g/L、CaCO370.84 μmol/L、MnSO4 65.39 μmol/L(1％丙烯酸诱导),NH4·H2O调节pH至7.0.培养基优化后酰胺酶产量由初始2554U/L提高到4156 U/L,为原始发酵培养基配方酶活产量的1.63倍.     

Statistical optimization of glucose oxidase production from Aspergillus niger NRC9 under submerged fermentation using response surface methodology

Response surface methodology (RSM), employing the fractional factorial design (FFD) was used to optimize the fermentation medium for the production of glucose oxidase (GOD) from a marine isolate (NRC9) of Aspergillus niger under submerged fermentation. The design was employed by selecting glucose, CaCO_3, ammonium phosphate and MgSO₄ concentrations as model factors by ‘one variable at a time’ experiment. A second-order quadratic model and response surface method showed that the optimum concentrations (g/l) glucose, 100; CaCO₃, 25; (NH₄)₂HPO₄, 1.8 and 0.4 of MgSO₄, resulted in an improvement of GOD production (170?±?0.88 U/ml) as compared to the initial level (109.81?±?1.38 U/ml) after four days of incubation at 200 rpm and 30 °C, whereas its predicted value obtained by the quadratic model was 164.36 U/ml. Analysis of variance (ANOVA) showed a high coefficient of determination value (R ²) of 0.967, ensuring a satisfactory adjustment of the quadratic model with the experimental data. This is the first report on production of glucose oxidase from a marine fungal isolate, Aspergillus niger NRC9, using statistical experimental design and response surface methodology in optimization of its production under submerged fermentation.